Diaphragm



G. E. MATHER.

DIAPHRAGM.

APPLlcAloN FILED JUNE 24, m9.

y, Patented Aug. 9, 119216 /n Ver) for.'

George E Maf/2er GEORGE E. NATI-EER, OF EAST ORANGE, NEV JERSEY, ASSIGNOR T0 WESTERN ELEC- TRC COMPANY, YORK.

ENCORPORATED, (Hi1 NEW YORK, N. Y., A CORPORATION 0F NEW DIAPI-IRAGM.

assenza,

T 0 all whom t may concern.

Be it known that l, GEORGE E. Marmara, a citizen of the United States, residing at East Orange, in the county of Essex, State of New Jersey, have invented certain new and useful Jimprovements in Diaphragms, of which the following is a full, clear, concise, and exact description.

This invention relates in general to da phragms and more particularly to a method for constructing a diaphragm especially suitable for use under water and at depths involving considerable pressure on the diaphragm.

ln the detectingapparatus used in connection with submarine signaling and also in similar apparatus used for detecting the faint sounds given off by the propellers of submarine vessels, it is often essential that the apparatus be mounted at a considerable distance below the surface'of the water, in which case the apparatus must of necessity be arranged to withstand the hydrostatic pressure exerted at the depth where it is to he used or else means must be provided to compensate for such pressure. Even when compeiisating means are provided, it is necessary to provide against slight changes in pressure due to sudden changes in depth. In the type of apparatus commonly used for this work, the detecting device consists of a substantially rigid casing equipped with one or more flexible diaphragms which serve as side walls and are responsive to vibrations in the surrounding medium. The casing itself is very easily made sufficiently strong to withstand the hydrostatic pressures exerted, but the diaphragm must be made to withstand such pressure and at the same time retain its fleXible character. Moreover, the diaphragm must be so made as to permit its being clamped to the casing in such a way as to provide a water-tight seal to prevent the entrance of water in the interior of the casing and the resulting damage to the delicate apparatus mounted therein. To withstand satisfactorily the pressures met with, and at the same time to insure a water-tight seal, it has been the practice to provide a soft rubber diaphragm equipped with a fabric insert to give it the necessary strength and having at its periphery a clamping ring which permits it being securely clamped in place. Much difficulty, however, has been experienced in obtaining such a diaphragm in which the Specification of Letters Patent.

Patented Aug. 9, 1921.

Application led June 24, 18M. Serial No. 306,357.

mechanical structure is uniform and in which there is vno tendency for the diaphragm to leak after being placed in service.

It is therefore the-obj ect of the present invention to provide a method of making a flexible diaphragm which will be capable of withstanding considerable pressure and which, as a result of its uniform mechanical structure, can be clamped in position to provide a water-tight seal. Y y To attain this object and in accordance with a feature of this invention, there is provided a method of constructing a diaphragm wherein the insert portion or reinforcing member is first molded into its final form, then placed between the two halves of an outer casing and the complete structure placed in a suitable mold and vulcanized into its final shape.

rlhis and other features of the invention will be more clearlyunderstood by reference to the accompanying drawing in which F igure l is a perspective view, partially in sec'- tion, of the insert before being molded into shape; Fig. 2 is a view of the insert molded into form and arranged between the two halves of the outer casing in the order in which the parts are to be assembled; and Fig. 3 is a perspective view partially in section of a completed diaphragm.

Referring now to the drawing, a sheet of fabric material, such as heavy canvas, is first treated with a rubber compound, during which process it is run between heavy rollers in order to force the rubber compound into all of the interstices of the fabric. From this sheet disks 5 and 6 having at their peripheries a series of projections or tabs 7 7, are then cut or punched. A ring 8 preferably formed of twine or equally compressible material is then laid alongside of each disk and the tabs are bent over as shown at 9. rlwo of the fabric disks equipped with the cord rings are then assembled back to back, as shown in Fig. l, and placed in a mold where they are pressed into the final shape desired, as shown at l0 of Fig. 2, and partially vulcanized in order that they may retain this shape after being removed from the mold.

The outer casing is made in two portions ll and l2 which are of rubber molded into the desired form and only partially vulcanized. rlfhe fabric insert 10 and the casing portions ll and l2 are then assembled in the order shown in Fig. 2 and placed into a mold where they are subjected to pressure and to the heat necessary to cause the further vulcanization and to produce a completed Vdiaphragm, as shown in partial cross-section in Fig. 3. The portion 11 of the outer case is provided with a yboss 13fin which is molded a metal insert 14 provided with the necessary threads to engage the threaded stem of'a microphone or telephone transmitter button" which can thus be mounted directly onthe diaphragm.

` In the completed diaphragm,fproduced by the method described, the fabric insertk isV of uniform structure, 'and is 'symmetrically' 1. The -`method of constructing VVa diaphragm which consists 'in incasing a rein# forcing member between two partially vulcanized members, placing the assembled parts in a mold and subjecting to pressureV and heat to cause further vulcanization.

2. The method' of coi'istructingl a diaphragm which consists in partially vulcanizing a reinforcing insert, incasing said reinforcing insert-between twofp'artially vulcanized members, placing the assembled parts in a mold and vulcanizing them into a unitary structure. Y Y 8. Thev method of constructing a diaphragm which consists in forming a reinforcing insert, molding said insert intoV 'the desired form andl partially vulcanizing, placing the insert ina mold between two partially vulcanized side pieces, and subjecting to pressure and heat to cause further vulcanization. Y y f 4.' rlhe method l of 'constructing a diaphragm which consists in formingfarein.-

forcing member of fabric material treatedwith a rubber compound, molding said memberinto the desired form and partially'vul- (canizing,rassembling said memberk between the halves of a two-piece casing composed of rubber partially'vulcanized, placing the assembl'ed parts in a mold, and applyingpressure and heat to vulcanize said parts into a unitary structure of the desired form.

5. The method of constructing adiaphragm vwhich consists in treating a sheet Y ofl fabric-material with rubber compound, cutting therefrom a pair of disks havinga plurality of projections at th'eirlperipheries,

placing a ring member adjacent to each disk,

folding over the projected portions to inclose said ring member, placing two of such Ydisks-back to back in a mold, applying pressure and heat toV form an insert of the desired form 'and' partially"fvulcanizing suoli insert, placing said insert in amold between two partially vulcanized vside pieces, and ap- 7 l ino' res'sureand heat to vulcaniz'e said membersA i sired shape.

nto a unitary structure of the de- 6. The method Y of constructing a diai phragmwhich consists in making a rein# I;

forcing insert of the required shape and two partially vulcanized incasing members one.

of which has a projection thereon in' which f is ymolded a metal insert and assemblingsaid reinforcing insert betweensaid incasingV members and vulcaiiizing said assembled members into a unitary structure.

.lnwitness whereof, l vhereunto subscribeV 1 my name this 17th day of June, A. D. 1919.

GEORGE E. MATHER. f 

